Genetic variation and phylogenetic relationship of Hypoderaeum conoideum (Bloch, 1782) Dietz, 1909 (Trematoda: Echinostomatidae) inferred from nuclear and mitochondrial DNA sequences

Objective: To explore genetic variations of Hypoderaeum conoideum collected from domestic ducks from 12 different localities in Thailand and Lao PDR, as well as their phylogenetic relationship with American and European isolates. Methods: The nucleotide sequences of their nuclear ribosomal DNA (ITS), mitochondrial cytochrome c oxidase subunit 1 (CO1), and NADH dehydrogenase subunit 1 (ND1) were used to analyze genetic diversity indices. Results: We found relatively high levels of nucleotide polymorphism in ND1 (4.02%), whereas moderate and low levels were observed in CO1 (2.11%) and ITS (0.96%), respectively. Based on these polymorphisms, the 20 ND1, 12 CO1, and 18 ITS haplotypes were classified, and several common haplotypes were observed in all samples. At least three major lineages, namely American, European and Asian lineages, have been classified by phylogenetic analyses based on ND1 sequences. Conclusions: Our report demonstrates that the ND1 gene is the most suitable genetic marker to explore genetic variation and phylogenetic relationship of Hypoderaeum conoideum. However, a combination of all loci for ND1, CO1 and ITS would be of great value toward further genetic investigation of this endemic worldwide parasite. Thus, comprehensive molecular genetic analyses of Hypoderaeum conoideum from its worldwide distribution is needed to further understanding of the evolutionary and systematic relationships of this parasite.

Zoonotic Echinostome Infections in Free-Grazing Ducks in Thailand

Free-grazing ducks play a major role in the rural economy of Eastern Asia in the form of egg and meat production. In Thailand, the geographical location, tropical climate conditions and wetland areas of the country are suitable for their husbandry. These environmental factors also favor growth, multiplication, development, survival, and spread of duck parasites. In this study, a total of 90 free-grazing ducks from northern, central, and northeastern regions of Thailand were examined for intestinal helminth parasites, with special emphasis on zoonotic echinostomes. Of these, 51 (56.7%) were infected by one or more species of zoonotic echinostomes, Echinostoma revolutum, Echinoparyphium recurvatum, and Hypoderaeum conoideum. Echinostomes found were identified using morphological criteria when possible. ITS2 sequences were used to identify juvenile and incomplete worms. The prevalence of infection was relatively high in each region, namely, north, central, and northeast region was 63.2%, 54.5%, and 55.3%, respectively. The intensity of infection ranged up to 49 worms/infected duck. Free-grazing ducks clearly play an important role in the life cycle maintenance, spread, and transmission of these medically important echinostomes in Thailand.

Diagnostic tools for human opisthorchaisis

Liver flukes of the family Opisthorchiidae consist of three medically important species, namelyClonorchissinensis, Opisthorchis felineus and Opisthorchis viverrini.These liver flukes infect at least 40 million people andestimated 700 million people worldwide are at risk of being infected. Of the three currently recognized species, only O. viverrini is classified as a type 1 carcinogen because of its role as an initiator of chronic inflammation leadingto subsequent development of cholangiocarcinoma (CCA). At present, there is no early diagnosis of CCA,the patients usually come to the doctor with advanced stages and die within 3 - 6 months. Importantly, this speciesof liver fluke is most commonly found in Southeast Asia. Especially, an estimated 9 million people are infectedin Thailand, that the cost of treatment of opisthorchiasis is approximately $120 million dollars annually for lostwages and medical care. High accuracy and sensitivity diagnostic methods are therefore required for efficientcontrol, prevention and treatment of opisthorchiasis. To date, there are three main methods for opisthorchiasisdiagnosis, i.e. parasitological method, which is standard method for microscopy-based identification of diagnosisstage such as egg in fecal sample. However, its sensitivity and specificity are low due to limitations of skilland expert of distinguishing egg morphology. Thus, immunological methods and molecular methods to identifythe opisthorchiasis were developed to improve sensitivity and specificity of diagnostic tools. This review articleaims to compile all opisthorchiasis diagnostic methods in order to obtain the suitable guideline for the effectivediagnosis of opisthorchiasis.

Hb E - alpha - thalassemia at Maharaj Nakhon Si Thammarat hospital

Both hemoglobin E (Hb E) and a-thalassemia are prevalence in Thailand. Hb E-a-thalassemia syndromes are therefore common. Individuals with these syndromes are at risk for both a- and b-thalassemia diseases. In this study, the prevalence of Hb E-a-thalassemia was examined on 204 Southern Thai subjects who were encountered at the Maharaj Nakhon Si Thammarat hospital. The a-thalassemia determinants examined using PCR methods included a-thalassemia 1 (SEA type), a-thalassemia 2 (3.7 kb and 4.2 kb deletions) and Hb Constant Spring gene (aCS). Hb E gene (bE) was confirmed in all cases using allele specific PCR. The prevalence of a-thalassemia 1, a-thalassemia 2 and aCS in  this Thai  population  were found to be 2.0 %, 15.7 % and 3.9 %,  respectively. As many as 11 Hb E genotypes were observed; 71.1 % heterozygous Hb E, 1.5 % heterozygous Hb E with heterozygous a-thalassemia 1, 10.3 %  hetetozygous Hb E with  heterozygous a-thalassemia 2 (3.7 kb), 1.5 % heterozygous Hb E with  heterozygous a-thalassemia 2 (4.2 kb), 2.9 % heterozygous Hb E with heterozygous aCS, 0.5 %  heterozygous Hb E with homozygous a-thalassemia 2, 1.0 % heterozygous Hb E with compound  heterozygous a-thalassemia 2 and aCS, 6.8 % homozygous Hb E, 0.5 % homozygous Hb E with  heterozygous a-thalassemia 1, 2.4 % homozygous Hb E with  heterozygous a-thalassemia 2 and 1.5 % b-thalassemia / Hb E disease. It was found that using hematological data alone it is very difficult to differentiate all these genotypes. It is therefore recommended for those with Hb E, whose couples are carriers of a-thalassemia 1, to be examined for a-thalassemia 1 especially when the level of Hb E is less than 25 % in order to prevent the Hb Bart’s hydrops fetalis and provide appropriate genetic counseling.